Flame failure and ignition control for fuel burners



Dec. 13, 1 c. K. STROBEL FLAME FAILURE AND IGNITION CONTROL FOR FUEL BURNERS 2 Sheets-Sheet 1 Filed July 5, 1951 INVENTOR. Cizaflles A. Sl'obel.

H15 HTTORNI'Y Dec. 13, 1955 c, K, STROBEL 2,726,717

FLAME FAILURE AND IGNITION CONTROL FOR FUEL BURNERS Filed July 3, 1951 2 Sheets-Sheet 2 IN V EN TOR.

Clzaples A. Slobel.

HIS AZZ ORNEY United States Patent FEAR/E3 FAKURE AND IGNITION CONTROL FOR FUEL BURNERS Charles K. Strobel, Pittsburgh, Pa., assignor to Robertshaw-Fuiton Controls Company, Greensburg, Pa., a corporation of Delaware Appfi fi July 3, 1 51, Serial No.- 23 ,066

5 Claims. (Cl- 161-9) This invention relates to systems for igniting fluid fuel burners and controlling such burners upon extinguishment of the flame. More particularly the invention relates to clock timers for turning on the fuel supply to a range oven with means to prevent such operation if no pilot flame flame is present to ignite such fuel supply.

It has been proposed that a simple timing device such as a four hour clock timer be employed for terminating an oven cooking operation automatically in place of the more complicated and expensive synchronous motor driven clocks heretofore supplied. Since the great majority of cooking operations are of less than four hours duration, the timer can be set by the housewife to start such operations and left to terminate them at a preselected time.

The apparatus employs a flame failure control in conjunction With the timer so that the cooking operation cannot be started in the absence of a pilot burner flame or, if started, is immediately terminated upon extinguishment of such flame. The arrangement envisions a single valve device for controlling the fuel supply to the main burner and governed by both the timerand the flame failure control. Thus, the operative connection between the valve, the timer and the flame failure control comprises a lever device which is manually operable to valve opening position only when the pilot burner is producing a flame. Otherwise, the flame failure control is effective for retaining the lever device in an inoperative position where it is ineffective to transmit opening movement to the valve device or to retain it to open position.

The manually operable means for the lever device comprises a simple push button for manipulation by the operator. If the flame failure control is responding to the pilot burner flame, then such manipulation operates the lever device to open the valve and set the timer in operation. Upon termination of the cooking operation the timer returns the lever device to its initial position and causes the valve device to close.

The timing device can be removed if desired and the control will operate as usual to shut-ofl. the flow of fuel in the event of extinguishment of the pilot flame. Under such conditions the time of cooking is controlled manually instead of automatically as will be apparent. Moreover, the control will fail safe and shut-off the flow of fuel should any failure or malfunctioning of the flame failure device occur.

The foregoing and other features, objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, wherein:

Fig. l is a schematic view partly in section of the flame failure control showing the valve in one operating position; and

Fig. 2 is a schematic view partly in section of the device of Fig. 1 showing another position of the valve; and

Fig. 3 is a schematic view of the flame failure and ig- ,nition control applied to the fuel burner.

2,726,717 Patented Dec- 3, 195.5

Re g m e part cularly to igs. ,1 an 2 of h drawings, the control as shown comprises a main casing 10 having a control valve casing 12 carried thereby at one end thereof. The control valve casing 12 is .pro vided with a hollow partition 14 forming a seat for a disk valve member 16. A coil spring 18 is operative between the valve m mbe 6 nd a clos re member 20 on the casing 12 for biasing the valve member 16 toward its seat on the partition 14. An .inlet 22 for fuel, such as gas, is provided in the casing '12 on the side of the partition 14 controlled by the valve member 16. Similarly, an outlet 24 for such fuel is providedin the casing 12 on the opposite side of the partition 14.

Motion transmitting means are employed for moving the valve member 16 from one controlling position to another, that is from the biased or closed position to an open position relative to the partition 14, The motion transmitting means includes an articulated arm 26 extending through the casing 10 and having a free end 28 projecting through an aperture 30 in an end wall 32. of the casing 12 opposite the closure member 20. The opposite end of the articulated arm .26 is .pivotally mounted, as at 34, on the wall .of the casing 10. Sealing means in the form of abellows 36 has its open end secured to the wall of the aperture 30 and its closed end positioned within the casing 12 for engagement with the end 28 of the articulated arm '26. A connecting stem 38 extends between the bellows 36 and the valve member 16 for transmitting opening force thereto from the articulated arm 26. Due to the relative positioning of the parts, when the valve member 16 .is seated on the partition 14, then thearticulated arm 26 occupies a downwardly bent position in the casing -10 as viewed in Fig. 1. However, by force applied adjacent to the underside portion of the articulation of the arm ,26, a straightening thereof first occurs and the articulation of the arm 26 is bent slightly upwardly as viewed in Fig. 2. In this position, the valve member 16 is opened and the movement of the arm 26 from a straight position to the slightly upward bent position does not appreciably affect the amount of opening of the valve member 16.

The desired valve opening force is obtained by manual operation of a push button 40 which extends transversely through the casing 10 on one side of the articulation of the arm 26. The push button 40 is biased outwardly of the casing 10 by a coil spring 42 and such movement is limited by a collar 44 carried by the push button 40 for engagement with the inner wall of the casing 10 As viewed in Fig.2, the inward movement of the push button 46 will serve to reverse the position of the articulated arm 26 causing axial movement of the end 28 relative to the partition 14 and consequent movement of the valve member 16 to open position against the bias of the coil spring 18.

The motion of the articulated arm 26 for opening the valve member 16 is also employed for setting a timing means in operation for predetermining the length of the cooking period. To this end, a reciprocable plunger 46 is slidably mounted in the wall of the casing 10 on the side of the articulation of the arm 26 opposite the push button 40. A head 48 on the plunger 46 serves to limit inward movement of the plunger 46 by engagement with the outer Wall of the casing 10. The timing means in this embodiment comprises a four-hour clock 50 of the springwound type and may take anyone of a number of well known forms. In this instance, areciprocable clock winding plunger 52 projects from the clock 50 and is positioned in operative engagement with the head 48 of the plunger 46. The plunger 52 is connected to the clock gear train so that axial movement of the plunger in one direction winds the clock and unwinding of the clock moves the P1 2 52 in. the other direction. Thus, upon upwardmovemenrof the plunger 46' to a predetermined extent, the clock 50 will be set for any desired time period up to four hours as indicated on the clock dial. It will be apparent, however, that the operation of, setting the clock plunger 46 serves as a stop for the'u'pward movementof the articulated arm 26'caused by biasof the spring 18.

The flame failure device of'this invention is effe'tctive,

as previously indicated,'to prevent the clock setting operation under certain conditions. To this end, the casing is provided with a suitable form of flame safety device which comprises the usual bulb 54, capillary tube 56 and actuating element '58 of a fluid-type thermal element. Preferably, the bulb 54 contains a quantity'of mercury which becomes completely vaporized when sufiiciently heated and serves to cause expansion of the actuating element 58 in a well-known manner. The actuating element 58 is supportedwithin the "casing 10 by a threaded stud 60 projectingthrough the wall of the casing 10 and se cured by a lock nut 62 in such position. The bulb 54 and capillary'tube 56 are exposed onthe exterior of the casing 10 for a purpose .which will be apparent hereinafter.

The restraining means previously mentioned for preventing the clock'setting operation takes the form of a perforated stop element 64 which is carried by the actuating element: 58 for axial movementin response to the expansion thereof. The articulated arm 26 extends through the perforated stop element 64 and is adapted to be engaged by. one wall 66 thereof in certain positions of movement. The wall 66 also serves as a stop against 1 4 her 64 is thus moved away from the adjacent portion of the articulated arm 26 and will not interfere with the a movement thereof.

The push button 40 maynow be manually operated to reverse the position of the articulated arm 26 causing axial movement of the free end 28 and operation of the valve member 16 to open position. During such movement of the articulated arm 26 the plunger 46 .is reciprocated in the casing 10 and the clock 50 is set by such movement for the desired cooking time. Since opening movement of the valve member 16 will admit fuel from the inlet 22 to the 'outlet 24 and thus to the main burner 68, such fuel is ignited by the flame from the pilot burner 70 and the oven is placed in normal running condition.

It will be apparent that in the event the pilot burner 70 does not produce a flame, then the bulb 54 of the thermal element remains unheated and the stop element 64 is positioned so that the apertured Wall 66 prevents movement of'the' articulated arm 26 by the push'button 40. Consequently, the valve member 16 cannot be moved to open position and no flow of fuel to the main burner 68 can occur.

In the event that a cooking operation is normally started 7 arm 26 to its initial position causing closure of the valve further upward movement of the articulated arm 26 in the event the clock 50 is removed.

Referring now to Fig. 3, a preferred assembly of the casing 10 in conjunction with a main fuel burner 68 and associated pilot burner 70 is illustrated. Thus, the usual main fuel cock 72 forthe oven of a domestic range is shown as provided in the usual manifold 74. The inlet 22 of the valve casing '12 is connected to the main fuel cock 72 and the outlet 24 'is connected to the main burner 68. A fuel supplyfor'the pilot burner 70 may be tapped directly from the main fuel cock 72 by way of a conduit 76. It will be apparent that the main fuel cock 72 may embody the conventional oven thermostat (not shown) for controlling the flow of fuel to the main burner 68 in accordancewith a desired setting.

Meansfor automatically igniting the pilot burner 70 are provided in this embodiment. This means takes the form of a so-called hot'type catalytic igniter 78 positioned in lighting proximity to the pilot burner 70 and continuously energized through a step-down transformer 80 having its primary connected to any commercial source of current supply, shown here as the line wires L1, L2. It will be apparent, however, that an automatic igniteris not essential but, if employed, many'other types may be substituted. 1

stop member 64; The apertured wall 66 of the stop mem-' member 16. In the event that the clock 50 is removed, or fails to operate, then the plunger 46 can be manually operated to return the articulated arm'26 to initial position thus cutting off the fuel supply to the main burner 68.

Should the thermal element comprising bulb 54, capillary tube 56 and actuating element 58 develop a leak, then the stop member 64 will occupy theinitial position since no expansion of the actuating element .58 can occur. Should such leak occur while the bulb 54 is heated and the articulated arm 26 is in its reversed position, then the device will fail safe since the arm 26 will be returned.

by operation of the apertured wall 66 to its initial position,

cutting oif .the supply of fuel to the main burner 68. j

having main and pilot burners, comprising control valve 1 means for the main burner biased to one controlling position, motion transmitting means including an articulated arm having a free end movable axially of said control valve means and operable for moving the same to another controlling position, manually operable means operatively engageable with said arm on one side thereof adjacent said articulation for setting said motion transmitting means in operative position, means responsive toa flame at the pilot burner including an expansible element, restraining means carried by said ,expansi'ole. element and operatively engageablewith said arm for preventing said setting operation in the absence of said flame, and means operatively engageable with said arm on the opposite side thereof adjacent said articulation and being responsive i to said setting operation for returningsaid motion transmitting means toinoperative position. a e a 2. A control apparatus'as claimed in claim 1 wherein the last said means includes atiming device. automatically operable after a predeterminedperiod. 1" 3. A control apparatusasclaimed' inclait'n z'wh'rein said timing device is separable from said arm, and manually operable means for returning said motion transmitting means to inoperative position in the absence of said timing device.

4. A control apparatus for fuel burning appliances having main and pilot burners, comprising control valve means for the main burner biased to one controlling position, motion transmitting means operable for moving said control valve means to another controlling position and including an articulated member having a free end movable axially of said control valve means between said controlling positions, manually operable means for setting said motion transmitting means in operative position and moving said control valve means to said other position, means responsive to a flame at the pilot burner for preventing said setting operation in the absence of said flame, and timing means responsive to said setting operation for returning said motion transmitting means to inoperative position and said control valve means to said one position after a predetermined period, said manually operable means and said timing means being effective respectively on opposite sides of said member adjacent said articulation.

5. A control apparatus as claimed in claim 4 wherein said flame responsive means includes restraining means operatively engageable with said member intermediate said articulation and one end thereof for preventing said setting operation.

References Cited in the tile of this patent UNITED STATES PATENTS 1,711,443 Boger Apr. 30, 1929 1,773,817 Leach Aug. 26, 1930 1,929,455 Smith Oct. 10, 1933 2,208,956 Allenbaugh July 23, 1940 2,303,672 Wantz Dec. 1, 1942 2,315,774 Couzens Apr. 6, 1943 

